<div id="fieldSet" class="field form-group formio-component formio-component-fieldset formio-component-fieldSet formio-component-multiple " ref="component">
  <fieldset>
    <legend ref="header" class="">
    </legend>
    <div class="card-body" ref="nested-fieldSet">
    </div>
  </fieldset>
  <div ref="messageContainer"></div>
</div>